Audio engineer quit job & gave up salary of $175,000 per year to start own business. Partial income statement below:

Revenues: 2010
Rev from sales of products / services $970,000

Operating costs & expenses:
Cost of products / services sold $355,000
Selling expenses $155,000
Admin expenses $45,000

Total operating costs $555,000

Income from operations $415,000
Interest expense (bank loan) $45,000
Legal start up expen $28,000
Income tax $165,000

Net income $177,000

Owner spent $100,000 of his savings to pay for capital startup cost for new business. In 2010 the owner could have taken earned 15% return by investing in stocks of other new companies with lower risk levels than starting up his own company.

1). what are total explicit, total implicit, total economic cost in 2010

2). what is the accounting profit in 2010

3). what is the economic profit in 2010

4). given the answer for #3, evaluate the new owner's decision to leave his previous job and start his own company?